Hydraulically actuated latches are used on some rocker arm assemblies to implement variable valve lift (VVL) or cylinder deactivation (CDA). For example, some switching roller finger followers (SRFF) use hydraulically actuated latches. In these systems, pressurized oil from an oil pump may be used for latch actuation. The flow of pressurized oil may be regulated by an oil control valve (OCV) under the supervision of an Engine Control Unit (ECU). A separate feed from the same source provides oil for hydraulic lash adjustment. This means that each rocker arm has two hydraulic feeds, which entails a degree of complexity and equipment cost. The oil demands of these hydraulic feeds may approach the limits of existing supply systems.
Using electromechanical latch assemblies instead of hydraulically-actuated latches can reduce complexity and demands for oil in some valvetrain systems. Electromechanical latch assemblies create the need to provide electrical power to the valvetrain. Valvetrain electrical power is also desirable for devices that could provide on board diagnostic information for cylinder deactivating and switching rocker arm assemblies.